1. Field of the Invention
The invention relates to a collecting device for cleaning balls at the outlet of a heat exchanger particularly a condenser, which comprises a pipe section with one or more screens, in each case pivotably arranged therein, and sloping with respect to the flow direction in the collecting position, as well as at least one discharge opening, at the in each case furthest downstream point, the pipe section being directly or indirectly connected via a bend and/or some other spacer to the chamber-like outlet.
2. Prior Art
In power stations, whose turbines are operated with steam, in sea water desalination plants and in certain chemical factories, heat exchangers and particularly condensers are used, whose cooling liquid is obtained from natural receiving streams, i.e. from rivers or the sea. Despite complicated filtering installations, within the heat exchanger pipes deposits and pollutants in the micro-range and macro-range appear in the heat transfer zone, and lead to an overall reduction in the heat exchanger efficiency, and consequently to an overall deterioration in the efficiency of approximately 2% in the case e.g. of a set of steam turbines. Thus, for a long time now cleaning systems have been used on such installations in which foam rubber balls are supplied to the heat exchanger inlet, are conveyed through the heat exchanger pipes under a slight pressing action by the pressure gradient and immediately following the heat exchanger are removed from the cooling liquid again with the aid of collecting devices.
The actual collecting element within such a collecting device comprises a screen or several screens, which under a definite inclination or obliquety drive the foam rubber balls towards a discharge opening for removing the same and they are then supplied to the heat exchanger inlet again by means of a suitable return system. The degree of inclination of the screens depends on the cooling liquid flow rate, the hardness of the sponge rubber balls and the gap between the individual bars of the screens constructed in rake-like manner. For cost reasons and often also for space reasons, a flat position of the screens is preferred, because the least space is required for this operating position, simultaneously the costs for producing the complete collecting device are comparatively low. As the inclination increases, the operating members must be made more robust and the support structure of each screen must be made large, which has an overall disadvantageous effect on costs.
When the incliniation is fixed account must be taken of the in each case least favourable operating mode, so that in such extreme cases a reliable removal of the sponge rubber balls from the cooling medium is ensured. A particularly unfavourable operating mode e.g. occurs if the sponge rubber balls have worn to their minimum permitted diameter, a particularly soft type has been used and the flow in the vicinity of the collecting dev1ce is very inhomogeneous, so that locally high flow rates occur.